Lubricant



Patented Jan. 1, 1946 LUBRICANT Robert L. May, Chicago, Ill., assignorto Sinclair Refining Company, New York, N. Y., a corporation of Maine NoDrawing. Application July 14, 1943, Serial No. 494,892

9 Claims. (01. 252-42.?)

This invention relates to a lubricating oil composition vhaving improvedcharacteristics, especially with respect to oxidation and corrosion.

In my co-pending application Serial No. 494,691 filed concurrentlyherewith, issued August 15, 1944, as Patent 2,356,074, I have describedand claimed a new class of organic-metal compounds comprising the zincsalts of organic compounds resulting irom the reaction of an aliphaticalcohol with a condensation product of a terpene, such as presentinturpentine, and phosphorus pentasulfide. The turpentine-phosphoruspentasulflde condensation products, and the materials resulting from thereaction thereof with the alcohol are the subject of my co-pendingapplications Serial No. 494,688, and Serial No. 494,689, respectively,each flied concurrently herewith, the latter having issued August 15,1944, as Patent 2,356,073.

I have now discovered that the zinc salts oi my first said application,and particularly those in the preparation of which an aliphatic alcoholhaving at least five carbon atoms per molecule is employed, areespecially eflective in repressing or inhibiting the deterioration oflubricating oil compositions and the corrosion oi metal parts in contacttherewith.

,I am at present unable definitely to identify by chemical formulaeither the zinc salts or the condensation products of turpentine andphosphorus pentasulilde or the products resulting from the reaction ofsaid condensation products with the alcohol. For convenience and brevityI shall herein refer to the former as my inhibitor. to the condensationproduct as the turpentine- P286 condensation product, and to thecomposition resulting from the reaction of the alcohol with thecondensation product as the intermediate'materialfeach of which ishereinafter more fully described.

Although the intermediate material itseli has been found to be adesirable component of lubrieating all compositions, the use of suchintermediate materials for this purpose is subject to certaindisadvantages. For instance, it is subject to the objection that theyhave somewhat acidic characteristics. due to phosphorus acidity whichhas been found to have a tendency to promote sludging of mineral oilcompositions. The lubri. eating oil compositions of my present inventionare free from this objection. I V

In general my inhibitor may be prepared by reacting zinc oxide with theintermediate material by intimately admixing the zinc oxide and theintermediate material with moderate heating. The product of thisreaction is then with advantage diluted and filtered to remove anyexcess or unreacted zinc oxide present. In the prepare tion of suchcompounds for use as a constituent of my improved lubricating oilcompositions, the diluent is with advantage a light neutral lubrieatingoil fraction which may be permitted to remain in the product.

The characteristics of my inhibitors vary somewhat, depending upon thecharacteristics of the turpentine-Pass condensation product, the natureand proportions of the alcohol reacted therewith to form theintermediate material, the condltions under which the reactions areeflected, and to some extent upon the proportions of zinc oxide and theintermediate material used in its production. Also the character of theinhibitor is influenced by the conditions under'which the zinc oxide isreacted with the intermediate material.

The reaction temperature employed in the last mentioned reaction in thepreparation of my inmum:- is with advantage maintained within the rangeof about 275 to 300 E. although reaction temperatures somewhat outsideof this range are permissible. Also, I have found it desirable to use anamount of zinc oxide somewhat in excess of that equivalent to the acidnumber of the intermediate material and to filter oi! unreacted, excesszinc oxide as previously indicated.

The lubricating oil composition of my present invention may consistsolely of the lubricating oil constituent and my inhibitor. However, theinhibitor of my present invention has been found to be compatible withother desirable lubricating oil addends and the inclusion of such otheraddends, especially addends oi the type known as detergents, is withinthe contemplation of my present invention and constitutes an importantaspect thereof.

The inclusion of certain so-called detergents. for instance, in internalcombustion engine lubricants, has been found highly advantageous. Anespecially eilective lubricating oil composition for the lubrication ofinternal combustion ensince and the like, contemplated by my presentinvention, is one comprising, in addition to the lubricating oilconstituent and my inhibitor, a

minor proportion of the calcium salt oi iso-octyl salicylate or thecalcium salt of capryl salicylate. These calcium salts have been foundparticularly eil'ective as detergents in lubricating 011 compositionsused in internal combustion engines.

as more iully described in the Patents 2,347,547

and 2,339,692, issued April 25, 1944, and January 18, 1944.respectively, on applications of Willard L. Finley.

A further highly eilectlve lubricating oil composition contemplated bymy present invention is one comprising, in addition to the lubricatingoil constituent and my inhibitor, a calcium petroleum sulionate as adetergent. Other detergents which may be used with advantage include thebarium phenoiate of sulfurized diamyl phenol such as currently marketedunder the trade name Aerolube B, metallic phenolates of sulfurizedtertiary amyl phenol, such as currently marketed under the trade namesCalcium Paranox" and "Barium Paranox," and various metallic soaps,either basic or neutral, metallic sulfonates, alcoholates, and alkoxidesand metallic derivatives of alkylated salicylic acid.

when used in conjunction with these detergents, particularl the calciumsalts, including calcium petroleum sulfonates previously mentioned,these detergents and my inhibitors have been found to complement eachother so that the eifectiveness of each is promoted. The tendency of thedetergent to promote oxidation of the oil at the termination of itsoxidation induction period is minimized by the presence of my inhibitorwithout destroying the effectiveness of either the detergent or theinhibitor.

The proportions of the inhibitor used in the compounding of my improvedlubricating oil compositions may be varied somewhat, but in any caseonly a minor proportion is used. In the absence of a detergent such aspreviously mentioned. generall satisfactory results have been obtainedby using proportions of the inhibitors within the range of about 0.01%to about 2% based on the weight of the oil constituent. Wheredetergents, such as the calcium salt detergents previously mentioned,are present, somewhat larger proportions, for instance, up to about 5%,may be used with advantage. In gear lubricants, for example, even largerproportions of my inhibitors may be employed.

As the lubricating oil constituent, various petroleum lubricating oilfractions may be used. For instance, solvent-treated Mid Continentneutrals or a blend of such neutrals with bright stock or asolvent-refined lubricating oi fraction from a Pennsylvania crude, orvarious blends of such lubricating oil fractions, may be employed.Characteristics of several such oils which have been used withadvantage. and which were used in the compounding of my lubricating oilcompositions hereinafter set forth as illustrative of my invention,appear in the following Table I, in which base oil A is a Mid-Continent250 neutral oil, base oil B is a solvent-treated Mid-Continent SAE 30oil, base oil C is also a solventtreated Mid-Continent oil, base oil Dis a blend of a Pennsylvania neutral and a Mid-Continent aircraft oil,and base 011 E is a solvent-refined Pennsylvania aircraftoil.

Table I Bose oil A B C D E Gravity. "A. P.I- 29.5 27.7 27. i 27.7 27.2Flash. F- l 405 435 485 455 548 Fike, "F .l l 480 4 I535 500 6!!) Vscosity, at 100 F., BUS. 249. 6 398. 4 442. 1 431. 7 1, 562 Viscosity.at 2l0 F., SUB.-- 49.0 57.3 57.5 59. 1 124.3 Viscosity index 92. 7 93.I] an. 6 85. 5 105. 5 Pull 5 i0 10 Carbon residue 0. 039 0B 0. 03 0. 370. 61 Add number. D. 05 0. 026 0. 025 Per cent sulfur 0. 24 0. l6 0. 06

The molar proportions 0! Pass, turpentine and alcohol, used in thepreparation of the intermediate material which I reacted with zinc oxidein the preparation of my inhibitors may be varied over a considerablerange. My inhibitors prepared from intermediate materials in thepreparation which the molar proportions of P285, turpentine and alcoholrespectively, are within the range of about 2:5:5 to about 2:5:3 havebeen found particularly desirable. However, this range may withadvantage be varied from about 2:4:4 to about 2:7:1.

The nature of the inhibitor is also considerably influenced by thenature of the alcohol used in the preparation of the intermediatematerial. Aliphatic alcohols generally which contain no fewer than livecarbon atoms per molecule may be used for this purpose. For example,those having from five to eighteen carbon atoms may be used withadvantage. Where an alcohol having fewer than five carbon atoms permolecule is used, the product has been found to lack satisractor oilsolubility. Alcohols which have been used with advantage in thepreparation of my inhibitors include straight-chain primary alcohols offive to eighteen carbon atoms per molecule, branched-chain primaryalcohols of five and six carbon atoms, and secondary alcohols of five toeight carbon atoms, respectively. My lubrieating oil compositionscompounded from inhibitors pre ared from intermediate materials in thepreparation of which capryl. normal rexyl or lauryl alcohol was usedhave been found to have particularly desirable characteristics. Thosecontaining inhibitors in the preparation of which capryl alcohol wasused have been found to be especially desirable.

Since the characteristics of my improved lubricating o l compositionsare somewhat influenced by the characteristics of the particularinhibitor employed, which in turn are influenced by the characteristicsof the intermediate material from which my inhibitors are prepared, adetailed description of the preparation and the characteristics of theparticular inhibitor used will be included in the specific illustrationsof my invention hereinafter set forth. It will be understood, however;that my invention is not limited to the use of these particularinhibitors illustrated nor with res ect to the method by which theinhibitor is prepared but includes lubricating oil composi tionscomprising the inhibitors herein described by whatever process theinhibitors may be made.

Generally, in the preparation of the turpentine. P255 condensat onproduct used in the preparation of my inhibitors, the weight ratio ofturpentine to P285 is with advanta e within the range Of about 1:1 toabout 3:1. when ratios higher than about 3:1 are used the product hasbeen found to contain considerable unreacted turpentine. Weight ratiosof about 3:2 have been found to give particularly desirable results.

The reaction of turpentine with has is highly exothermic and proceedsspontaneously after being initiated by slight heating. A desirablemethod of effecting this reaction is to heat the turpentine in a. vesselto about 200' FL, and then, without further heating, slowly stirring inthe phosphorus pentasulflde in the powdered form. The heat of reactionis great and consequently the sulfide should be added slowly so as toavoid the possibility of the reaction's becoming uncontrollable. For thepurposes of my present invention, it is desirable that the temperatureduring this addition not be permitted to exceed about action. water waseliminated and there was considerable foaming of the mixture. when thewater of reaction was eliminated, as evidenced by the cessation of thefoaming. the temperature was slowly increased to a maximum of 300' F.,and held at that temperature for about 2 hours. The reaction product wasthen diluted with 0853 grams of a Mid-Continent neutral oil. hereinaftermore fully described, heated to 250 R, and illtered as previouslydescribed.

The product was found by analysis to have an acid number of 10.7 and tocontain 3.79% phosphorus, 8.48% sulfur and 2.06% zinc, by weight.

Exlmrna IV 080 grams (5 moles) of turpentine was placed in a 2-iiterflask, such as previously described, and stirred while being heated to225 F. 444 grams of powdered phosphorus pentasulfide was then added tothe turpentine at such a rate that the temperature did not rise above250 F. After all the sulfide had been added. the temperature of themixture was raised to 300 F., and maintained at that temperature forabout 8 hours, at the end of which period all the phosphorus and sulfidewas dissolved. The mixture was then permitted to cool to 250 F., and 264grams of "Pentasol," a commercial mixture of army] alcohols, was added.The temperature was then maintained at 220 for an additional hour.

The intermediate material thus prepared was found by analysis to have anacid number of 74.6 and a saponincation number of 181.1 and to contain9.23% phosphorus and 21.5% sulfur by weight.

750 grams of this intermediate material and 120 grams of zinc oxide wereheated with stirring in a 2-liter beaker for 1 hour at 180 F.. andfinally heated at 300 F., for 30 minutes. Thereafter, 2250 grams of theMid-Continent neutral oil, used in Example III, was added, the mixtureheated to a temperature of 250 and the product filtered at thistemperature. n cooling, a slight precipitate formed. Upon the additionof further lubricating oil to portions of the product in amountssuflicient to produce concentrations of about 1% to of the product, ahaze formed in the oil mixtures but was readily removed by filtrationwithout detriment to the product.

The product was found by analysis to have an acid number of 15.5 and tocontain, 1.88% phosphorus, 5.10% sulfur and 1.07% zinc, by weight.

Exams: V

680 grams (5 moles) of steam-distilled turpentine was placed in a3-liter flask, such as previously described, and heated to 225 F. Therewas then added 444 grams (2 moles) of powdered phosphorus pentasulfidein 25 to 30 gram portions at such a rate as to hold the temperaturebelow 250 F. when all of the phosphorus pentasulfide was added, themixture was heated to 300 F. and maintained at this temperature for 3hours, at the end of which period the phosphorus pentasulfide wasdissolved. The mixture was then cooled to 250 F., and 306 grams (3moles) of 2-ethyl butanol-i was added over a period of 30 minutes withcontinuous stirring and the temperature held at about 200 to 220 F. for1 hour after the addition of the alcohol.

The intermediate material thus produced was found by analysis to have anacid number of 74.9 and a saponiflcation number of 176.2 and to contain8.96% phosphorus and 22.1% sulfur by weight,

1185 grams of this intermediate material and grams of zinc oxide wereheated and stirred in a 2-liter beaker, as in Example IV, and 3555 gramsof the Mid-Continent neutral oil used in Example III was added, themixture heated to 250 F.. and filtered while hot. As in Example theproduct was not entirely soluble in the lubricating oil fraction in thisconcentration but produced clear solutions upon further filtration. Theproduct was found by analysis to have an acid number of 18.3 and tocontain 1.98% phosphorus, 5.42% sulfur and 1.10% zinc by weight.

Exmu: VI

A 3-liter, round-bottomed flask. fitted with a stirrer, was charged with680 grams of turpentine. The turpentine was heated to 200 F., heatingdiscontinued and 444 grams of powdered phosphorus pentasulflde wasadded, with stirring, in portions of about 25 to 30 grams each and at arate such that the temperature did not rise above 250 F. After all thephosphorus pentasulfide had been added, the temperature was raised to300 R, and maintained at, that temperature for 3 hours, at the end ofwhich period all of the sulfide was dissolved. Thereafter, the mixturewas cooled to 250 F. and 306 grams of normal hexyl alcohol was added andthe temperature of the mixture held at about 200 F. for about 1 hour.

The resultant intermediate material was found by analysis to have anacid number of 74.0 and a saponification number of 172.1 and to contain8.20% phosphorus and 21.57% sulfur by weight.

685 grams of this intermediate material and 120 grams of zinc oxide wereadmixed and heated as in Example IV, the product diluted with 2055 gramsof the Mid-Continent neutral oil and filtered. This product was notcompletely oil-soluble but upon further dilution and filtration a clearsolution was obtained.

The product was found by analysis to have an acid number of 19.9 and tocontain 2.13% phosphorus, 5.51% sulfur and 1.58% zinc, by weight.

Exam-1.x VII 340 grams (2.5 moles) of turpentine was heated to 200 F.,and 222, grams (1 mole) of powdered phosphoruspentasulfide was addedslowly as previously described. After the sulfide was all dissolved, 279grams (1.5 moles) of Lox-oi," a, commercial mixture of alcohols madefrom hydrogenated fatty acid esters from palm oil and containing from 10to 14 carbon atoms per molecule, was added and the mixture maintainedfor 1 hour at a temperature of 220 1''.

The resultant intermediate material was found by analysis to have anacid number of 67.2 and a saponification number of 147.3 and to contain7.18% phosphorus and 19.80% sulfur, by weight.

654 grams of this intermediate material and 40 grams of zinc oxide wereplaced in a 1500 milliliter beaker and stirred while being heated slowlyto 300 F. At about F. to 220 1". some foaming and water evolution tookplace. The heating extended over a period of about 1 hour. Thereafter,the product was diluted by the addition of 654 grams of theMid-Continent neutral oil, the mixture heated to 250 F. and filtered.

The product was found by analysis to have an acid number of 21.9 and tocontain 3.48% phosphorus, 8.65% sulfur and 1.71% zinc by weight.

Exams: VIII To a turpentine-P28: condensation product. prepared as inExample VII, there was added 405 grams (1.5 moles) of octadecyl alcoholand the mixture maintained at 220 F. for 1 hour. The resultingintermediate product was found by analysis to have an acid number of57.2 and a resinous solid.

absence of excess turpentine. normally a brittle, It is with advantageprepared from turpentine, either steam distilled turpentine or gumspirits, consisting mainly of alpha pinene,

saponii'lcation number or 131.6 and to contain 5 a bi-cyclic terpenehaving the empirical for- 6.52% phosphorus and 17.20% sulfur by weight.mula Cml-lm. Pure alpha pinene, and other more 742 grams of thisintermediate material and costly terpenes, will react similarly withP235, but G m of zinc oxide were placed in a 1500 for reasons includingeconomical considerations, milliliter beaker and stirred while beingslowly I prefer to use the more readily available turheated to 300 F.Thereafter, the product was 0 pentine. The turpentine used in thespecific exdiluted by the addition of 742 grams of the Midamplesappearing herein was a technical grade Continent neutral lubricating oiland the mixsteam-distilled wood turpentine comprising ture heated to 250F., and filtered. This prodabout 90% alpha pinene. was found by analysisto have an acid number The advantages of my present invention with of19.8 and to contain 2.91% phosphorus, 6.90% respect to oxidation andcorrosion character- S u nd Z nc by weig t. istics of my improvedlubricating oil composi- The IOU-pale oil diluent used in the foregoingtions are illustrated by their mean oxygen ab- Examples I and II and theMid-Continent neusorption rates as compared with the oxygen abtral Oil ued i t e o e oing Examples III to sorption rate of the base oil and thecorrosion VIII. inclusive. had e following characteristics: losses ofbearing metal in contact with the respective lubricants. 100mm M-lmcombFor example, the previously noted base oil A oil nent neutral was foundby conventional tests carried on at 360 F. to have a mean oxygenabsorption rate g n g A. P. 22.1 21.9 of 2.8 cc. per minute in theabsence of a d er nt, Firms 1:13::11:1 3?. i3; copper-lead bearing metalor other oxidation giscosity atglil sus-.. 107.8 197.8 catalyst. Acomposite of the inhibitors of the ms w S 5 foregoing Example I, II, IXto XXI inclusive, and XXV was prepared and was found by analysis Furtherillustrations of the inhibitors used in to have an acid number of 15.2and to contain the compounding of my improved lubricating P ph rus,4.62% sulfur, and 1.07% zinc. oil compositions appear in the followingtabulaby weight. By compounding 0.5 weight per cent tion. The respectivemembers of the group were of the composite inhibitor with base oil A,the prepared according to the general procedure premean oxygenabsorption rate of the oil was reviously described. In each of theseexamples, duced to 2.3 cc. per minute. Under the s me test the alcoholused was capryl alcohol. For 21 conditions the mean oxygen absorptionrate of more complete description of the resultant inthis base oil wasreduced to 2.2 cc. per minute hibitor specific reaction conditions andproporby compounding therewith 0.2 weight per cent tions of the severalconstituents. together with of this composite inhibitor. thecharacteristics of the intermediate materials In the presence ofcopper-lead bearing metal used in their preparation, are included. themean oxygen absorption rate of base oil A g'ggff g g ggi g g iPreparation of final product Analy of 11118 product Example NO P 8Conaof Zn PSl' Tail-112cm Alcohol, Acid Sap intermediate Zinc Max.product Asia P,wt., s, at, wt"

2 1.9 3.1 71.1 was 8.04 20.4 150 so 250 25 7.75 1.1111 1.1.10 1.1111 24.9 3.1 71.1 138.8 8.04 20.4 150 190 100 10.7 T.Si 10.0 F1. 70 z 5 555.6 136.1 6.77 16.0 L000 174 300 25 13.3 L74 -l.l-i 1.157 2 5 6 55.6136.1 6.77 16.9 500 51 300 25 12.4 l.7l 4.22 0.70 1 10 10 114.2 146.07.011 11.1 222 211 25a 25 11.1 1.73 4.110 1 m 4 1o 10 114.2 146.9 1.0917.4 222 30 2.10 25 7.11 1.11.1 1 11 1.111 4 l0 6 7L0 162:!) 8.07 230.3210 20 250 25 10.5 2.10. :'"L 1.10 4 l0 0 7L0 162.9 8.07 20.3 2l0 302.30 25 10.4 2.0L *2 1.1;! 4 l0 6 71.0 162.9 8.07 20.3 2l0 30 2510 25ll) 1 2.015 'i 1.1: 4 10 6 71.0 152.0 8.07 20.3 210 40 300 2.; lat 2.015.11; 1.17 4 10 6 71.0 1 .9 8.07 20.3 e45 150 sec 25 10.1; 1.111 4.72117.1 4 ll) 6 71.0 162.9 8.01 20.3 520 135 275 25 0.0 Lilli 5.1T LLo 615 9 92.1 ass 20.1 520 i851 2:5 :5 111.1 1. lszl c. 6 l5 9 92.1 7.33 20!1.514 120 300 5b 2.1a 4.0.] 0.471 J U7 6 15 a 65 92.1 7.88 11:14 1.51411011 so 21.0 i 1.111 .Lfi 1. 11 6 l5 9 05 02.1 7.88 20.4 1,514 ts loo 03: 0 11111;. u m 1.... 0 l5 0 64.9 l56.8 8.02 20.8 520 1a.) .175 as on rinf -l. 1 0.7] B 15 0 64.0 150.8 8.02 20.13 1.511. 100 .1011 .11 i 20.20.0. 1m. 1 c.

From e r oing specific illustrations it apwas 25.6 cc. per minute andthe bearin mot-.11 pests that the combining ratios of zinc oxide andcorrosion loss was 5.8 mes. By c mp the intermediate material variessomewhat with therewith 0.5 weight per cent of the previously the excessof zinc oxide present and also the noted composite inhibitor the meanoxygen abtemperature at which the reaction is efiected. scrption ratewas, under identical test conditions. The duration of the reactionperiod also appears reduccd to cc. per minute and no corrosion toinfluence the zinc content of the finished in- 70 loss was apparent.hibltor. As previously noted, the presence of r Further the oxidationinduction period of the considerable excess of zinc oxide during thereuninhibited blend oi the base oil with l... Oi [ix ctionls usuallydesirable. calcium isooctyi salicylatc detergent W about Theturpentine-P285 condensation product used minutes. and by compoundingtherewith 0.5. m the p eparation of my inhibitors is. in the 75 of thisinhibitor the oxidation lllCliiCliOIl-ili'llUEl was essentiallyeliminated, the mean oxygen absorption rate over a period 01 650 minutesbeing only 1.54 cc. per minute.

A blend of this base oil and 1% of the calcium iso-octyl salicylic had,in the presence of copperlead bearing metal an oxidation inductionperiod of 107 minutes and during the test the bearing metal corrosionloss was found to be 11 mgs. By compounding with this blend 0.5% of theinhibitor, the oxidation induction period was substantially eliminated,the mean rate or oxygen absorption during the first 300 minutes or thetest being 1.2 cc. per minute and during the remainder of the 490 minutetest being 3.4 cc. per minute. indicating that the calcium of thedetergent was largely though not completely deactivated. Further, duringthe test of the inhibited blend no bearing metal corrosion loss wasexperienced.

Using only 0.3% of this inhibitor in the blend of base oil A and 1% ofthe calcium iso-octyl salicylic detergent, the oxidation inductionperiod in the presence of copper-lead hearing was increased from 107 to239 minutes and the bearin metal corrosion loss was decreased from 11mgs. to only 1.8 mgs.

Further, iron naphthenate in the presence of the lubricating oilcompositions of my present invention is substantially deactivated. Forinstance, in the presence of iron naphthenatc equivalent to 0.01% FesOsthe mean oxidation absorption rate oi the uninhibited detergent blendwas 45.6 cc. per minute due to the pro-oxidant catalytic action of theiron naphthenate. The mean oxygen absorption rate of my improvedlubricating oil composition comprising the same blend and 0.5% of thiscomposite inhibitor had, under identical conditions a mean oxygenabsorption rate of 4.6 cc. per minute.

The results of these and other oxidation and corrosion tests of myimproved lubricating oil compositions, compounded with various of theinhibitors specifically identified herein, as compared with theoxidation and corrosion characteristics of the base oil alone, are setforth in the following Table 11. These tests were carried out at atemperature of 360 F. and no detergent was present. Copper-lead bearingmetal was present in the respective lubricants during these tests. Theidentity of the particular inhibitor used has reference to the specificexamples of my inhibitors previously set forth herein.

lead bearing metal, and the corrosion loss 01 the bearing metal was 11mgs. as previously noted. By the addition 01' various inhibitors of mypressent invention, in proportions as indicated in the following TableIII, the oxidation induction period and corrosion losses were as thereinindicated. The identity of the particular inhibitor used has referenceto the specific examples of my inhibitors previously set forth herein.

Table III Inhibitor 0x en in- Test Base (fiction Bearing metal NIL gilor Plumb period corrosion V lend Identity tion, minutes loss percent 1 ANone I07 11 2 A Composite 0. 5 300 None 3.. A Ex. IV. 0. 5 296 \lonc4... A Ex. V 0.5 264 4.9 5 A EX.V 0.75 240 0.7 5. A Ex. V1... 0.5 203None 7 A Ex. VII" 0. 5 278 2. 5 8... A Ex. VII.. 0.75 320 None A Ex.VIII. 0.5 l9!) 8.3 A Ex. VIII. 0.75 330 Nom- The results of these testsshow that in each instance oxidation of the oil and corrosion of thebearing metal were materially repressed by the inhibitors of myinvention, though in some instances, more of the inhibitor was requiredfor substantiall complete protection than in others. These and othertests indicate that the calcium of the detergent, which normally acts asa pro-oxidant following the induction period, is substantiallydeactivated in my improved inbricating oil compositions.

The deactivation of the calcium by my detergent is not limited to thecalcium of the calcium salicylates but is also eifective against othercalcium-containing detergents. For example, a blend of base oil B and2.2% of a calcium petroleum sulfonate detergent in the absence ofpro-oxidant bearing metal had a mean oxygen absorption rate, by theconventional tests previously noted, of 8.7 cc. per minute and, in thepresence of copper-lead bearing metal. had a mean oxygen absorption rateof 13.7 cc. per minute and a bearing metal corrosion loss of 5.2 mgs.The lubricating oil composition of my present invention resulting fromthe compounding of the various indicated proportions of the compositedetergent previously described with Table II this base oil and 2.2% ofthe calcium petroleum sulfonate detergent had, in the presence of cop-Inhibitor per-lead bearing metal, oxidation and corrosion T t B Mean'mBearing metal characteristics as set forth in the following es useabsorption, corrosion No. all M m PtIiODOI- licogmiml lossmgs Table IV:

Bil y on 31118.

pem'm Table IV 25.6 5.8 Mean rate of Bearing 0.6 3.3 None Test N0Inhibitor, Ogabsorptlon metal corpercent cc./min./l00 rosion loss. 0.56.3 3.0 gins. mgs. 0.7a 4.2 0.1 0.5 as 4.2 0. 7a 1.1 0.6 a a 5.1 2. 90.5 6- 3.9 0.4 4.1 None 0. 75 as 1.6 o. 5 s. s o. 4 0.6 13.2 5.6 1.0 4.7None 1.0 7.2 0.6 as 14.2 4.4 The results of these tests and tests ofsimilar The inhibitor used in test No. 2 was the composite inhibitor,previously identified.

A blend of base oil A with 1% of the calcium iso-octy'l salicylic had anoxidation induction perind of 107 minutes, in the presence ofcopperlubricating oil compositions indicated that the inhibitors of mypresent invention are compatible with, and are generally eflective ininhibiting the pro-oxidant tendencies of, these and similarcalcium-containing detergents. In the lubricating oil compositions ofTable IV the amount oi." the'calclum' petroleum sulfonate used (2.2%)was equivalent to 0.055% calcium in the oi], blend. It appears thereiromthat 0.3% of the composite inhibitor was lnsuflicient completely toinhibit this amount of calcium. However, 0.4% was sufflcient toeliminate completely the bearing metal corrosion loss. The amount ofinhibitor required for optimum results varied somewhat with theparticular inhibitor used.

The eflectiveness of my improved lubricating oil composition ininhibiting oil deterioration and bearing metal corrosion further appearsfrom results of tests made in accordance with the procedure recommendedby the American 50- ciety of Testing Materials, published October, 1942,and entitled Proposed method of test for oxidation characteristics ofheavy duty crankcase oils" and conveniently known as the ChevroletEngine Test." These tests were run on the base oil alone and also onlubricating oil compositions comprising such base oils compounded inaccordance with my present invention.

Results representative of such tests are set forth in the followingTable V. In test No. 1 base oil alone was used. In test No. 2 thelubricating oil composition consisted of base oil C compounded with0.125% of the previously described composite inhibitor, and in testsNos. 3 and 4 the lubricating oil composition tested consisted of baseoil 0, 1% of said composite inhibitor and a detergent. The detergentused in the compounding of test No. 3 was 2% of the calcium salt ofcapryl salicylic, and that of the composition of test No. 4 was 5% of acalcium soap of oxidized petroleum acids. The engine cleanliness rating,analysis of the lubricants at the end of the tests, and the corrosionlosses per half bearing of copper-lead bearing metal during the testswere as indicated in Table V.

From these tests it appears that oil deterioration and bearing corrosionare inhibited by my improved lubricating oil compositions whether or nota detergent is present. The results of test No. 2 indicate, however,that for optimum results a higher proportion of the inhibitor should beused.

Results of similar tests of lubricating oil compositions comprising baseoll D compounded with a detergent and various proportions of thepreviously noted composite inhibitor, in the presence of Cu-Pb bearingmetal, are set forth in the following Table VI. In test No. 1 thereof,the oil composition tested consisted of base oil D,1% of the inhibitorand 5% of the previously mentioned calcium soap of oxidized petroleumacids, as the detergent. The oil composition of test No. 2 consisted ofbase oil D with 0.75% of the inhibitor and an amount of the calciumpetroleum sulionate equivalent to 0.054% calcium in the blend. Theproportions of these addends are in each instance based on the weight ofthe lubricating oil constituent.

Table VI Test No.

Engine cleanliness rating 9B Used oil tests:

Napntna insoluble ..pcrccut. l. 05 0 97 011Gb, soluble 0. 37 U. 22 VNeutralization No... 1.9 l. 76 Bearing metal corrosion loss grams 0.0715 0. 041

That aircraft lubricating oils such as that herein designated base oilE, are likewise materially improved by compounding in accordance withthe present invention is illustrated by the results of tests of this oilalone and of my improved lubricating oil compositions consisting of suchoil and a minor proportion of my inhibitor. In conducting such tests Ihave used the procedure described in an article by H. C. Mougeyappearing in Refiner and Natural Gasoline Manufacture, 15, 493-8 (1936).In these tests the lubricant charge was 24 lbs., the bearing temperaturewas 300 F., the journal speed was 2530 R. P. M.. and the bearing loadwas 2700 lbs. per square inch. In these tests the oil in the sumpoxidized rapidly and became corrosive to copperlead bearings. Thebearings were weighed and replaced at intervals, the test beingcontinued until a total loss in weight of 100 mgs. per half bearingshell had occurred.

Results representative of such tests are set forth in the followingTable VII. The inhibitor used in test No. 2 was that previouslyidentified as my composite inhibitor.

In addition to inhibiting oxidation and corrosion, I have found thelubricating oil conditions of my present invention to have definitedetergent properties, even in the absence oi detergents such aspreviously described. This tact is illustrated by the tests of Table Vwherein the engine cleanliness rating was increased from 91 to 95 bycompounding with the base 011 0.125% of my inhibitor, no other detergentbeing present.

I claim:

1. A lubricating oil composition comprising a petroleum lubricating oiland a proportion, etiective to retard oxidation of the composition. ofthe reaction product of zinc oxide and an organic compound resultingfrom the reaction of a monohydroxy aliphatic alcohol, having not fewerthan 5 carbon atoms per molecule, with a condensation product ofturpentine and phosphorus pentasulfide.

2. A lubricating oil composition comprising a petroleum lubricating oiland about 0.1% to 2%, based on the weight of the oil constituent. of thereaction product of zinc oxide and an organic compound resulting fromthe reaction of a monohydroxy aliphatic alcohol, having not fewer than 5carbon atoms per molecule, with a condensation product of turpentine andphosphorus pentasulfide.

8 assaess 3. A lubricating oil composition comprising a normal hexylalcohol with a condensation prodpetroleum lubricating oil, a calciumsalt of an not of turpentine and phosphorus pentasulflde. isooctylsalicylate detergent and about 0.1% to 7. A lubricating oil compositioncomprising a of a reaction product of zinc oxide and an petroleumlubricating oil and a proportion, eforganic compound resulting from thereaction of 5 fective to retard oxidation of the composition, of amonohydroxy aliphatic alcohol, having not the reaction product of zincoxide and an organic fewer than 5 carbon atoms per molecule, with acompound resulting from the reaction of lauryl condensation product ofturpentine and phosalcohol with a condensation product of turpenphoruspentasulfide. tine and phosphorus pentasulflde.

4. A lubricating oil composition comprising a 10 8. A lubricating oilcomposition comprising a petroleum lubricating oil. a calcium petroleumpetroleum lubricating oil, a calcium salt of an sulfonate detergent anda proportion, effective to octyl salicylate and a proportion, effectiveto reretard oxidation of the composition, of the re tard oxidation ofthe composition, of the reaction action product of zinc oxide and anorganic comproduct of zinc oxide and an organic compound pound resultingfrom the reaction of a monoresulting from the reaction of a monohydroxyhydroxy aliphatic alcohol, having not fewer than aliphatic alcohol,having no fewer than live car- 5 carbon atoms per molecule, with acondensabon atoms per molecule, with a condensation tion product ofturpentine and phosphorus pentaproduct of turpentine and phosphoruspentasulfide, sulfide.

5. A lubricating oil composition comprising a 9. A lubricating oilcomposition comprising a petroleum lubricating oil and a proportion,efpetroleum lubricating oil, a calcium derivative of fectiv to retardoxidation of the composition, an alkylated salicylic acid as a detergentand a of the reaction product of zinc oxide and an proportion, effectiveto retard oxidation oi the organic compound resulting from the reactionof composition, of the reaction product of zinc oxcapryl alcohol with acondensation product of ide and an organic compound resulting from theturpentine and phosphorus pentasulfide. reaction of a monohydroxyaliphatic alcohol 6. A lubricating oil composition comprising a havingno fewer than 5 carbon atoms per molepetroleum lubricating oil and aproportion, efcule with a condensation product of turpentine fective toretard oxidation of the composition, and phosphorus pentasulfide.

of the reaction product of zinc oxide and an organic compound resultingfrom the reaction of ROBERT L. MAY.

CERTIFICATE OF CORRECTION. Patent NO. 2,592,255. January 1, wi e.-

ROBERT L. MAY.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page lfirst column, line 514, for 21.5?5" read --2l.57%-; page 5, secondcolumn, line 3%. for "the" first occurrence. read this-; page 7, secondcolumn, line B, 'Ia IeVI, for '0 9'? read 97-; and that the said LettersPatent should be read with this correction therein that the same mayconform to the record of the case in the Patent Office.

Signed and sealed this 9th day of April, A. D. 19%.

Leslie Frazer (Seal) First Assistant Commissioner of Patents.

8 assaess 3. A lubricating oil composition comprising a normal hexylalcohol with a condensation prodpetroleum lubricating oil, a calciumsalt of an not of turpentine and phosphorus pentasulflde. isooctylsalicylate detergent and about 0.1% to 7. A lubricating oil compositioncomprising a of a reaction product of zinc oxide and an petroleumlubricating oil and a proportion, eforganic compound resulting from thereaction of 5 fective to retard oxidation of the composition, of amonohydroxy aliphatic alcohol, having not the reaction product of zincoxide and an organic fewer than 5 carbon atoms per molecule, with acompound resulting from the reaction of lauryl condensation product ofturpentine and phosalcohol with a condensation product of turpenphoruspentasulfide. tine and phosphorus pentasulflde.

4. A lubricating oil composition comprising a 10 8. A lubricating oilcomposition comprising a petroleum lubricating oil. a calcium petroleumpetroleum lubricating oil, a calcium salt of an sulfonate detergent anda proportion, effective to octyl salicylate and a proportion, effectiveto reretard oxidation of the composition, of the re tard oxidation ofthe composition, of the reaction action product of zinc oxide and anorganic comproduct of zinc oxide and an organic compound pound resultingfrom the reaction of a monoresulting from the reaction of a monohydroxyhydroxy aliphatic alcohol, having not fewer than aliphatic alcohol,having no fewer than live car- 5 carbon atoms per molecule, with acondensabon atoms per molecule, with a condensation tion product ofturpentine and phosphorus pentaproduct of turpentine and phosphoruspentasulfide, sulfide.

5. A lubricating oil composition comprising a 9. A lubricating oilcomposition comprising a petroleum lubricating oil and a proportion,efpetroleum lubricating oil, a calcium derivative of fectiv to retardoxidation of the composition, an alkylated salicylic acid as a detergentand a of the reaction product of zinc oxide and an proportion, effectiveto retard oxidation oi the organic compound resulting from the reactionof composition, of the reaction product of zinc oxcapryl alcohol with acondensation product of ide and an organic compound resulting from theturpentine and phosphorus pentasulfide. reaction of a monohydroxyaliphatic alcohol 6. A lubricating oil composition comprising a havingno fewer than 5 carbon atoms per molepetroleum lubricating oil and aproportion, efcule with a condensation product of turpentine fective toretard oxidation of the composition, and phosphorus pentasulfide.

of the reaction product of zinc oxide and an organic compound resultingfrom the reaction of ROBERT L. MAY.

CERTIFICATE OF CORRECTION. Patent NO. 2,592,255. January 1, wi e.-

ROBERT L. MAY.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page lfirst column, line 514, for 21.5?5" read --2l.57%-; page 5, secondcolumn, line 3%. for "the" first occurrence. read this-; page 7, secondcolumn, line B, 'Ia IeVI, for '0 9'? read 97-; and that the said LettersPatent should be read with this correction therein that the same mayconform to the record of the case in the Patent Office.

Signed and sealed this 9th day of April, A. D. 19%.

Leslie Frazer (Seal) First Assistant Commissioner of Patents.

